Battery cells, in particular lithium ion battery cells, but also metal hydride battery cells such as nickel metal hydride battery cells, or lithium polymer battery cells or other chemical energy storage devices, are becoming of ever greater importance in the motor-vehicle industry. In particular owing to the demand for alternative power concepts, for example hybrid power or pure electrical power, the storage of electrical energy is of immense significance for future motor vehicle manufacture.
The use of new types of battery cells, for example lithium ion battery cells, as electrical energy storage devices for electric motors in motor vehicle manufacture has proven advantageous. These storage devices store a large amount of energy in a small volume. Additionally such battery cells are only limitedly subject to an ageing process. In particular, no “memory effect” occurs in them. A large number of charging cycles can therefore take place, so that the lifetime of the battery cells substantially corresponds to that of a vehicle.
Most battery cells, however, only provide low voltages of between one volt and several tens of volts. These low voltages are far from sufficient to power an electric motor of an electrical vehicle. Furthermore, most battery cells only provide an electric charge of between 1 and 5 ampere-hours, which is not sufficient to power a vehicle for typical use. For this reason, battery cells are connected together to form so-called battery pack assemblies. In this case, a plurality of individual battery cells can be connected to one another in series, so that the output voltage of the battery pack assembly is multiplied according to the number of battery cells connected in series.
In the construction of battery pack assembly, the terminals of the battery cells are typically interconnected by conductive bus bars e.g. plated copper bars in order to provide sufficient current carrying capability. The bus bars are usually fastened to the terminals of the battery cells using a threaded fastener. The time required to assemble such a battery array is long due to the time needed to attach the bus bars to each battery terminal using a threaded fastener. In addition, special precautions must be taken by the assembly operators while attaching the bus bars to the terminals due to the possibility to exposure to electrical voltage from the live battery cells.
Another problem in the construction of battery pack assembly is accommodating the alignment of adjoining terminals which is subject to tolerance because of production-related variations in the production of battery cells. This means that when two battery cells are arranged next to one another substantially in a plane, the terminals may not be coplanar.
In known battery modules, there is then the problem of compensating for tolerances of the battery lengths furthermore arises. There is also the problem of connecting a plurality of battery cells to one another electrically in a working step which is simple to carry out.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.